This recent large randomised controlled trial from Moorfields Eye Hospital examined visual results in patients receiving one of two commercially available diffractive multifocal implants, made by Zeiss and Alcon respectively.

Given that the purpose of these special implants is to gain spectacle independence, it is surprising that only 82% and 77% of patients actually achieved complete spectacle independence respectively.

Furthermore, some 44% and 37% of patients reported haloes as an adverse effect that was at least a little bothersome:

http://www.ncbi.nlm.nih.gov/m/pubmed/25537197/?i=1&from=ophthalmology%20122:700